This study is designed to define the pharmacokinetics and aspects of the metabolism of amphotericin B employing a standard bioassay technique in association with high performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry-computer analysis (GC-MS-COM). Concentrations of amphotericin B and its metabolites will be measured serially in the serum and urine of patients with diverse systemic mycotic infections. Studies will be conducted to determine the characteristics of amphotericin B binding to serum proteins by equilibrium dialysis, ultrafiltration, and red blood cell partition methods. The influence of variations in renal function on a) the relative concentration of metabolites and parent compound in body fluids, b) renal clearance, and c) selected pharmacokinetic parameters will be ascertained.